Oled display substrate and manufacturing method thereof, oled display device, and brightness compensation method

ABSTRACT

The present disclosure relates to an OLED display substrate including a base substrate, a thin film transistor array layer and a planarization layer on the base substrate, and an anode, a pixel definition layer, a cathode, and a light emitting layer on a side of the planarization layer away from the base substrate, the pixel definition layer defining pixel regions, the light emitting layer being located on a side of the pixel definition layer away from the base substrate. The display substrate further includes a light guide that is in contact with the light emitting layer and is used to lead out light from the light emitting layer, so as to test the led-out light and adjust light emission.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the priority of Chinese PatentApplication No. 201910285986.4 filed on Apr. 10, 2019, the contents ofwhich are incorporated herein in their entirety by reference.

TECHNICAL FIELD

The present disclosure relates to the field of display productmanufacturing technology, and in particular to an OLED display substrateand a manufacturing method thereof, an OLED display device, and abrightness compensation method.

BACKGROUND

At present, voltage driving mode is usually adopted as active drivingmode for OLED (Organic Light-Emitting Diode) devices. Compared withcurrent driving, voltage driving can be implemented with simplestructure, suitable for large-size display, and has high driving speed.On the other hand, the scheme of voltage driving needs to compensate fornon-uniformity of Thin Film Transistors (TFTs), power supply voltagedrop, and uneven display brightness caused by the non-uniformity ofOLED. The current driving mode realizes the grayscale control bydirectly providing certain current, which can compensate thenon-uniformity of the TFTs and the power supply voltage drop well.However, the writing time for low grayscale current is too long and thestructure is complicated. The digital driving mode uses thelight-emitting time modulation method to achieve different gray levels,that is, the longer the light-emitting time per unit time, the greaterthe duty cycle, and the higher the brightness perceived by human eyes.However in such driving mode, the circuit is frequently switched,resulting in high power consumption, and more grayscales cannot berealized due to the scanning speed and its scanning drive structure.

SUMMARY

The present disclosure provides an OLED display substrate whichincludes: a base substrate, a thin film transistor array layer and aplanarization layer on the base substrate, and an anode, a pixeldefinition layer, a cathode, and a light emitting layer on a side of theplanarization layer away from the base substrate, the pixel definitionlayer defining pixel regions, the light emitting layer being located ona side of the pixel definition layer away from the base substrate, thedisplay substrate further including a light guide that is in contactwith the light emitting layer and is used to lead out light from thelight emitting layer, so as to test the led-out light and adjust lightemission.

Optionally, the pixel definition layer includes a first pixel definitionsub-layer and a second pixel definition sub-layer stacked in a directionaway from the base substrate, the light guide is located between thefirst pixel definition sub-layer and the second pixel definitionsub-layer, and the light guide includes a contact portion exposedoutside the pixel definition layer to be in contact with the lightemitting layer.

Optionally, a refractive index of the light guide is greater than arefractive index of the pixel definition layer.

Optionally, the light guide includes a first side in contact with thelight emitting layer and a second side opposite to the first side, thecontact portion is located on the first side, and a concave-convexstructure is provided on the second side so that light entering thelight guide is totally reflected on the second side.

Optionally, the light guide includes a plurality of row light guidesarranged in parallel with data lines, a number of the row light guidesis equal to a number of rows of the pixel regions, and each row of thepixel regions is connected to one corresponding row light guide.

Optionally, the light guide further includes at least one column lightguide, and the at least one column light guide intersects the row lightguides.

Optionally, the thin film transistor array layer includes a gateinsulation layer, a first planarization layer, an etching stop layer, apassivation layer, and a second planarization layer provided on the basesubstrate;

-   -   a first opening is provided at a first position of the gate        insulation layer, the first planarization layer is located in        the first opening;    -   a second opening is provided at a second position of the etching        stop layer and the passivation layer, the second opening        penetrates the etching stop layer and the passivation layer, a        portion of the etching stop layer in the second opening forms a        first etching stop sub-layer, the second planarization layer is        filled between the first etching stop sub-layer and rest of the        etching stop layer, a portion of the passivation layer in the        second opening forms a first passivation sub-layer, the second        planarization layer is filled between the first passivation        sub-layer and rest of the passivation layer;    -   the second planarization layer has a third opening at the second        position to expose the first passivation sub-layer, the first        etching stop sub-layer and the first passivation sub-layer        constitutes the light guide, wherein the light guide further        includes an anode which is provided between the first        passivation sub-layer and the light emitting layer,    -   wherein orthographic projections of the second and third        openings on the base substrate fall within an orthographic        projection of the first opening on the base substrate.

Optionally, a refractive index of the etching stop layer is greater thana refractive index of the first planarization layer, the refractiveindex of the etching stop layer is greater than a refractive index ofthe second planarization layer, a refractive index of the passivationlayer is greater than the refractive index of the first planarizationlayer, and the refractive index of the passivation layer is greater thanthe refractive index of the second planarization layer.

Optionally, the thin film transistor array layer includes a gateinsulation layer, a gate, a first metal film layer, an etching stoplayer, a passivation layer, a second metal film layer, and aplanarization layer provided on the base substrate;

-   -   the first metal film layer and the gate are manufactured in a        same layer and formed at a first position;    -   a fourth opening is provided at a second position of the etching        stop layer and the passivation layer, the fourth opening        penetrates the etching stop layer and the passivation layer, a        portion of the etching stop layer in the fourth opening forms a        second etching stop sub-layer, the second metal film layer is        filled between the second etching stop sub-layer and rest of the        etching stop layer, a portion of the passivation layer in the        fourth opening forms a second passivation sub-layer, the second        metal film layer is filled between the second passivation        sub-layer and rest of the passivation layer;    -   the planarization layer has a fifth opening at the second        position to expose the second passivation sub-layer;    -   the second etching stop sub-layer and the second passivation        sub-layer constitutes the light guide,    -   wherein an orthographic projection of the fifth opening on the        base substrate falls within an orthographic projection of the        fourth opening on the base substrate.

The present disclosure further provides a manufacturing method of anOLED display substrate including:

-   -   forming a thin film transistor array layer on a base substrate;    -   forming a planarization layer;    -   forming an anode and a pixel definition layer on a side of the        planarization away from the base substrate;    -   forming a light emitting layer on a side of the pixel definition        layer away from the base substrate;    -   forming a light guide, the light guide being in contact with the        light emitting layer and used to lead out light from the light        emitting layer to test the led-out light and adjust light        emission; and    -   forming a cathode on the light emitting layer.

Optionally, the pixel definition layer includes a first pixel definitionsub-layer and a second pixel definition sub-layer, and after the step offorming the planarization layer, the method includes:

-   -   forming the anode and performing patterning process;    -   forming the first pixel definition sub-layer and performing        patterning process;    -   forming the light guide on the first pixel definition sub-layer        and performing patterning process;    -   forming the second pixel definition sub-layer on the first pixel        definition sub-layer and the light guide, and performing        patterning process;    -   forming the light emitting layer on the second pixel definition        sub-layer; and    -   forming the cathode on the light emitting layer.

Optionally, the light guide is composed of a passivation layer and anetching stop layer, and the method includes:

-   -   forming a gate layer and a gate insulation layer on the base        substrate;    -   etching the gate insulation layer at a first position to form a        first opening;    -   forming a first planarization layer in the first opening;    -   forming the etching stop layer and the passivation layer;    -   etching the passivation layer and the etching stop layer to form        a second opening penetrating the passivation layer and the        etching stop layer, a portion of the etching stop layer in the        second opening forming a first etching stop sub-layer, a portion        of the passivation layer in the second opening forming a first        passivation sub-layer;    -   forming a second planarization layer, a part of the second        planarization layer filled in the second opening and the first        passivation layer are in contact with each other, so as to cover        the first passivation sub-layer and the first etching stop        sub-layer;    -   etching the second planarization layer at a second position to        form a third opening exposing the first passivation sub-layer.

Optionally, the light guide is composed of a passivation layer and anetching stop layer, and the method includes:

-   -   forming a gate and a first metal film layer in a same layer on        the base substrate, wherein the first metal film layer is formed        at a first position;    -   forming a gate insulation layer, a passivation layer and an        etching stop layer; performing patterning process on the        passivation layer and the etching stop layer to form a fourth        opening, a portion of the etching stop layer in the fourth        opening forming a second etching stop sub-layer, a portion of        the passivation layer in the fourth opening forming a second        passivation sub-layer;    -   forming a second metal film layer in the fourth opening, the        second metal film layer being filled between the second etching        stop sub-layer and rest of the etching stop layer and filled        between the second passivation sub-layer and rest of the        passivation layer;    -   forming the planarization and performing patterning process to        form a fifth opening;    -   forming the node, the pixel definition layer, the cathode, and        the light emitting layer in pixel regions defined by the pixel        definition layer.

The present disclosure further provides an OLED display device,including the above OLED display substrate and a brightness compensationmechanism which is connected to the light guide to collect brightnessinformation of the light emitting layer and compensates brightness of acorresponding pixel region according to the brightness information.

Optionally, the brightness compensation mechanism includes:

-   -   a brightness information collection module configured to collect        the brightness information of the light emitting layer in each        pixel region, the brightness information including brightness        corresponding to a plurality of grayscales in one-to-one manner;    -   a grayscale brightness curve acquisition module configured to        acquire a measured grayscale brightness curve according to the        brightness information;    -   a grayscale compensation value acquisition module configured to        compare the measured grayscale brightness curve with a standard        grayscale brightness curve to acquire a grayscale compensation        value of a preset grayscale;    -   a compensation module configured to perform brightness        compensation according to the grayscale compensation value.

Optionally, the OLED display device further includes a brightnesscorrection module which includes:

-   -   a standard photoelectric sensor connected to the light guide to        acquire a measured brightness L1 of the light emitting layer in        a current pixel region;    -   an image sensor configured to acquire an actual brightness L2 of        the current pixel region;    -   a brightness correction coefficient acquisition unit configured        to acquire a brightness correction coefficient A=L2/L1 according        to the measured brightness L1 and the actual brightness L2;    -   the brightness information acquired by the brightness        information collection module is a product of a first brightness        acquired through the light guide and the brightness correction        coefficient.

The present disclosure further provides a brightness compensation methodapplied to the above OLED display device, including steps of:

-   -   collecting the brightness information of the light emitting        layer in each pixel region;    -   acquiring a measured grayscale brightness curve according to the        brightness information;

comparing the measured grayscale brightness curve with a standardgrayscale brightness curve to acquire a grayscale compensation value ofa preset grayscale;

-   -   performing brightness compensation according to the grayscale        compensation value.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1a shows a schematic diagram of a voltage-based external electricalcompensation wiring layout in the related art;

FIG. 1b shows a circuit diagram of a voltage-based external electricalcompensation in the related art;

FIG. 2 shows a film layer structure of an OLED display substrate in therelated art;

FIG. 3a shows a first schematic diagram of a wiring layout in anembodiment of the present disclosure;

FIG. 3b shows a circuit diagram in an embodiment of the presentdisclosure;

FIG. 4 shows a first schematic diagram of a film layer structure of anOLED display substrate in an embodiment of the present disclosure;

FIG. 5 shows a structural diagram of a light guide in an embodiment ofthe present disclosure;

FIG. 6a shows a first schematic diagram of a partial film layerstructure of an OLED display substrate in an embodiment of the presentdisclosure;

FIG. 6b shows a second schematic diagram of a partial film layerstructure of an OLED display substrate in an embodiment of the presentdisclosure;

FIG. 7 shows a second schematic diagram of a film layer structure of anOLED display substrate in an embodiment of the present disclosure;

FIG. 8 shows a schematic diagram of a partial film layer structure inwhich no third opening is provided in a planarization layer;

FIG. 9 shows a third schematic diagram of a film layer structure of anOLED display substrate in an embodiment of the present disclosure;

FIG. 10a shows a second schematic diagram of a wiring layout in anembodiment of the present disclosure;

FIG. 10b shows a third schematic diagram of a wiring layout in anembodiment of the present disclosure;

FIG. 11a shows a fourth schematic diagram of a film layer structure ofan OLED display substrate in an embodiment of the present disclosure;and

FIG. 11b shows a fifth schematic diagram of a film layer structure of anOLED display substrate in an embodiment of the present disclosure.

DETAILED DESCRIPTION

The technical solutions of the embodiments of the present disclosurewill be described clearly and thoroughly in conjunction with theaccompanying drawings of the embodiments of the present disclosure inorder that the objects, technical solutions, and advantages of theembodiments of the present disclosure clearer. Obviously, the describedembodiments are some of the embodiments of the present disclosure,rather than all of the embodiments. Based on the described embodimentsof the present disclosure, all other embodiments obtained by a person ofordinary skill in the art fall within the protection scope of thepresent disclosure.

As for the voltage driving mode that has more product applications, theexisting compensation mode in the related art can be classified intoelectrical compensation and optical compensation according to the objectof compensation. Electrical compensation can be classified into internalcompensation and external compensation. Internal compensation mainlycompensates for TFT Vth, while external compensation can compensatemore, including TFT Vth, mobility and OLED aging. Of course, these donot represent all electrical parameter differences, let alonedifferences other than electrical parameters. Therefore, thecompensation has certain limitations, and the brightness uniformityafter compensation is not good enough; in addition, electrical parametercompensation usually has a compensation range, and if the uniformity ofelectrical parameters is poor, the uniformity will still be poor aftercompensation.

Optical compensation directly uses brightness as the object ofcompensation. After compensation, high uniformity of pixel brightnesscan be achieved. Therefore, optical compensation is highly expected.However, the existing optical compensation technology uses a CCD camerato collect the brightness of each pixel for compensation. This methodrequires relatively large equipment, so it is limited to one-timecompensation before the product leaves the factory, and cannotcompensate for the brightness difference caused by the aging of theproduct used for a long time.

FIGS. 1a and 1b are schematic diagrams of the principle of voltage-basedexternal electrical compensation used at present. FIG. 1a is a schematicdiagram of the planar layout of components and wires of the circuit, andFIG. 1b is an equivalent circuit diagram of the circuit layout shown inFIG. 1a . In the layout diagram of the pixel unit shown in FIG. 1a , theregions marked with a letter R, G, B, or W refer to individualsub-pixels. For example, the mark R indicates a red sub-pixel, Gindicates a green sub-pixel, B indicates a blue sub-pixel, and Windicates a white sub-pixel. As shown in FIGS. 1a and 1b , take the bluesub-pixel marked with letter B as an example, where the transistor T1 isconnected to the light emitting element, the transistor T2 is connectedto the data line Data, the transistor T3 is connected to the sensingline Sense, and C is the storage capacitor.

The above sensing line Sense is connected to the 4 sub-pixelssequentially through an inverted T-shaped circuit, and the pixel unitcompensation circuit is connected to the sensing line Sense through thetransistor T3 in each sub-pixel, thereby realizing the sensingcollection of electrical parameters.

The film layer structure shown in FIG. 2 is a schematic cross-sectionalview, taken along the AA′ direction, of the film layer structurecorresponding to the schematic diagram of the planar layout ofcomponents and wires of the circuit shown in FIG. 1a . As shown in FIG.2, the display substrate includes a base substrate 1, a thin filmtransistor array layer 2 and a planarization layer 8 located on the basesubstrate 1, and an anode 3, a pixel definition layer 7, a cathode 5 anda light emitting layer located on the planarization layer 8. The pixeldefinition layer 7 defines a pixel region, and the light emitting layer4 is located on a side of the pixel definition layer 7 away from thebase substrate.

In the voltage-based external electrical compensation mode, the TFT/OLEDcurrent (pixel driving current) of each pixel through the internalsensing circuit and the external sensing IC (driving circuit) isextracted and converted into a digital signal for processing. At thesame time, the driving voltage corresponding to the TFT/OLED current isalso recorded, so that the I-V curve corresponding to each TFT and OLEDcan be known. Then, a compensation coefficient is calculated and fedback to a source driver for compensation.

The present disclosure can realize the collection of the brightness ofeach pixel by replacing the sensing line in FIG. 1a by a light guide,calculate the brightness grayscale curve of each pixel, and thencalculate the amount of grayscale that needs to be compensated, therebyrealizing the brightness difference compensation of the display.Compared with the structure of the existing OLED device, its structureremoves the electrical parameter sensing structure and adds the opticalparameter sensing channel. Since the ultimate purpose of the electricalcompensation is to correct the difference in brightness, the opticalcompensation used in the present disclosure is more direct than theelectrical compensation, and has the advantages of better compensationeffect and simple structure.

As shown in FIG. 4, the embodiment provides an OLED display substratewhich includes a base substrate 1, a thin film transistor array layer 2and a planarization layer 8 on the base substrate 1, and an anode 3, apixel definition layer 7, a cathode 5, and a light emitting layer 4 onthe planarization layer 8. The pixel definition layer 7 defines pixelregions, the light emitting layer 4 is located on a side of the pixeldefinition layer 7 away from the base substrate. The display substratefurther includes a light guide 101 that is in contact with the lightemitting layer 4 and is used to lead out light from the light emittinglayer 4. The light guide 101 is used to test the led-out light andadjust light emission.

As shown in FIGS. 3a and 3b , the embodiment replaces the sensing linein FIG. 1 by the light guide 101 in contact with the light emittinglayer 4. Referring to FIG. 3a , the light guide 101 includes a row lightguide 01 arranged in parallel with the data line and a plurality ofcolumn light guides 02 perpendicular to the data line. An end of eachcolumn light guide 02 is in contact with the light emitting layer of aplurality of pixel regions to lead out the light from the plurality ofpixel regions to the row light guide 01. The row light guide 01 isconnected to an external sensor to acquire the brightness ofcorresponding pixel region to implement the collection of pixelbrightness. Compared with FIGS. 1a and 1b , the circuit structure of theOLED display substrate in the embodiment is simplified, the transistorT3, the sense line and other corresponding wires are omitted.

The light guide 101 may have various specific structures. For thearrangement of the light guide 101 in an implementation (firstimplementation) of the embodiment, please refer to FIGS. 4, 6 a and 6 b.FIG. 4 shows a schematic cross-sectional view, taken along the directionAA' in FIG. 3a , of the film layer structure of the OLED displaysubstrate of the embodiment. As shown in FIGS. 6a and 6b , the pixeldefinition layer 7 includes a first pixel definition sub-layer 102 and asecond pixel definition sub-layer 103 that are stacked, the light guide101 is located between the first pixel definition sub-layer 102 and thesecond pixel definition sub-layer 103, and the light guide 101 includesa contact portion exposed outside the pixel definition layer 7 to be incontact with the light emitting layer 4.

In this implementation, a refractive index of the light guide 101 isgreater than a refractive index of the pixel definition layer 7.

The larger the refractive index of the light guide 101 relative to therefractive index of the pixel defining layer 7 is, the better, therebyenhancing the total reflection of light in the light guide 101, and thusenabling the light to going out along the light guide 101.

In this implementation, the light guide 101 includes a first side 1011in contact with the light emitting layer 4 and a second side 1012opposite to the first side 1011, and the contact portion is located onthe first side 1011. In order to increase the amount of light led outfrom the light guide 101, a concave-convex structure is provided on thesecond side 1012 so that the light entering the light guide is totallyreflected on the second side 1012, as shown in FIG. 5.

The arrangement of the concave-convex structure increases thepropagation angle of light, allowing more light to be totally reflectedat the interface between the light guide 101 and the pixel defininglayer 7. Of course, there can be other ways to increase the amount ofcollected light, which is not limited here.

The concave-convex structure may have various specific structures. Inthe embodiment, the concave-convex structure is a saw-tooth structure,as shown in FIG. 5, but it is not limited thereto.

A specific manufacturing method of the OLED display substrate in thisimplementation is as follows:

-   -   forming the thin film transistor array layer 2 on the base        substrate 1;    -   forming the planarization layer 8;    -   forming the anode 3, and performing patterning process;    -   forming the first pixel definition sub-layer 102 and performing        patterning process on it;    -   forming the light guide 101 on the first pixel definition        sub-layer 102 and performing patterning process;    -   forming the second pixel definition sub-layer 103 and performing        patterning process;    -   wherein the second pixel definition sub-layer 103 should be        arranged such that the contact portion of the light guide 101        used to be in contact with the light emitting layer 4 is not        covered (that is, the contact portion is not covered by the        second pixel definition sub-layer 103), so that the light guide        101 can be in contact with the light emitting layer 4 directly        to receive the incoming light; the second side 1012 of the light        guide 101 (the side that is opposite to the first side 1011 on        which the contact portion is provided) is covered so as to        achieve the total reflection of light.    -   forming the light emitting layer 4 in the pixel regions defined        by the pixel definition layer 7 composed of the first pixel        definition sub-layer 102 and the second pixel definition        sub-layer 103;    -   forming the cathode layer 5 and an encapsulation layer 6        sequentially.

For the manufacturing of the film layer structure on the OLED displaysubstrate in this implementation, refer to FIGS. 6a and 6b . The lightentering the light guide 101 propagates along the C′C direction.

It should be noted that, FIG. 4 simplifies the overall film layerstructure, only reflects the up-and-down relationship between layers,and does not describe the specific features of the film layers indetail. FIGS. 6a and 6b show the specific features of partial film layerstructure. The following description will also only describe thepositional relationship between the film layers, without reflectingspecific features.

In another implementation (second implementation) of the embodiment, thethin film transistor array layer 2 includes a gate insulation layer 21,a first planarization layer 81, an etching stop layer 22, a passivationlayer 23, and a second planarization layer 82 provided on the basesubstrate 1;

-   -   a first opening is provided at a first position of the gate        insulation layer 21, the first planarization layer 81 is located        in the first opening;    -   a second opening is provided at a second position of the etching        stop layer 22 and the passivation layer 23, the second opening        penetrates the etching stop layer 22 and the passivation layer        23, as shown in FIG. 7, a portion of the etching stop layer 22        in the second opening forms a first etching stop sub-layer 221,        the second planarization layer 82 is filled between the first        etching stop sub-layer 221 and rest of the etching stop layer        22, a portion of the passivation layer 23 in the second opening        forms a first passivation sub-layer 231, the second        planarization layer 82 is filled between the first passivation        sub-layer 231 and rest of the passivation layer 23;    -   the second planarization layer 82 has a third opening at the        second position to expose the first passivation sub-layer 231,        so that the first passivation sub-layer 231 leads light out of        the light emitting layer 4 (through the anode 3), wherein        orthographic projections of the second and third openings on the        base substrate fall within an orthographic projection of the        first opening on the base substrate.

The first etching stop sub-layer 221 and the first passivation sub-layer231 jointly form a light guide structure, which functions similarly tothe light guide 101 described above with reference to FIG. 4.

Compared with the first implementation, in this implementation, thelayout diagram of components and wires of the circuits of the OLEDdisplay substrate may be similar to that shown in FIG. 3a , but thespecific structure and arrangement position of the light guide 101 havechanged. The light guide 101 is arranged on the side of the secondplanarization layer 82 away from the anode 3, as shown in FIG. 7.

In this implementation, a refractive index of the first etching stopsub-layer 221 is greater than a refractive index of the firstplanarization layer 81, the refractive index of the first etching stopsub-layer 221 is greater than a refractive index of the secondplanarization layer 82, a refractive index of the passivation layer 23is greater than the refractive index of the first planarization layer81, and the refractive index of the passivation layer 23 is greater thanthe refractive index of the second planarization layer 82.

With the above solution, the light from the light emitting layer 4enters the first passivation sub-layer 231 and the first etching stopsub-layer 221, and is totally reflected at the interface between thefirst passivation sub-layer 231 and the second planarization layer 82,and is totally reflected at the interface between the first etching stopsub-layer 221 and the first planarization layer 81, so that lightpropagates in the light guide formed by the first passivation sub-layer231 and the first etching stop sub-layer 221, and is led out.

The manufacturing method of the OLED display substrate in thisimplementation is as follows:

-   -   forming a gate layer and a gate insulation layer on the base        substrate 1;    -   etching away the gate insulation layer at a position (the first        position) of the orthographic projection of the light guide 101        on the gate insulation layer in the planar layout shown in FIG.        3a , to form the first opening, and then forming a first        planarization layer 81 on the first opening;    -   forming an IGZO (indium gallium zinc oxide) film layer, an        etching stop layer 22, a source, a drain, and a passivation        layer 23 sequentially;    -   etching the passivation layer 23 and the etching stop layer 22        to form the second opening penetrating the passivation layer 23        and the etching stop layer 22 (the passivation layer 23 and the        etching stop layer 22 located in the second opening are named        the first passivation sub-layer 231 and the first etching stop        sub-layer 221, respectively);    -   forming a second planarization layer 82, wherein a part of the        second planarization layer 82 is filled in the second opening        and in contact with the first planarization layer 81, so as to        cover the first passivation sub-layer 231 and the first etching        stop sub-layer 221;    -   etching the second planarization layer 82 to form a third        opening that exposes the first passivation sub-layer 231;    -   the third opening is arranged to make the light emitting layer 4        be in contact with the first passivation sub-layer 231 after the        light emitting layer 4 is formed, so that light can propagate in        a total reflection manner in the light guide 101 composed of the        first passivation sub-layer 231 and the first etching stop        sub-layer 221. If the third opening is not formed, the first        passivation sub-layer 231 cannot contact the light emitting        layer 4, that is, the light guide 101 cannot contact the light        emitting layer 4; thus, no matter what angle the light enters        the light guide 101, it will exit at the same angle, and the        light cannot propagate in the light guide 101, as shown in FIG.        8.

It should be noted that the anode 3 is made of a transparent conductivematerial, such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide),which does not affect the light from the light emitting layer 4 enteringthe first passivation sub-layer 231.

In another implementation (third implementation) of the embodiment, alayout diagram of components and wires of the circuit of the OLEDdisplay substrate is shown in FIG. 3a , and a schematic diagram of thefilm layer structure of the OLED display substrate is shown in FIG. 9.The thin film transistor array layer 2 includes a gate insulation layer21, a gate, a first metal film layer 91, an etching stop layer 22, apassivation layer 23, a second metal film layer 92 and a planarizationlayer 8 provided on the base substrate 1;

-   -   the first metal film layer 91 and the gate are manufactured in a        same layer and formed at a first position;    -   a fourth opening is provided at a second position of the etching        stop layer 22 and the passivation layer 23, the fourth opening        penetrates the etching stop layer 22 and the passivation layer        23, as shown in FIG. 9, a portion of the etching stop layer 22        in the fourth opening forms a second etching stop sub-layer 222,        the second metal film layer 92 is filled between the second        etching stop sub-layer 222 and rest of the etching stop layer        22, a portion of the passivation layer 23 in the fourth opening        forms a second passivation sub-layer 232, the second metal film        layer 92 is filled between the second passivation sub-layer 232        and rest of the passivation layer 23;    -   the planarization layer 8 has a fifth opening at the second        position to expose the second passivation sub-layer 232 so that        the second passivation sub-layer 232 leads light out of the        light emitting layer 4 (through the anode), wherein orthographic        projections of the fourth and fifth openings on the base        substrate fall within the orthographic projection of the first        opening on the base substrate;    -   the second etching stop sub-layer 222 and the second passivation        sub-layer 232 jointly form a light guide structure, which        functions similarly to the light guide 101 described above with        reference to FIG. 4.

With the above technical solution, since the cathode 5 is above thelight emitting layer 4, the light emitted by the light emitting layer 4is confined to propagate inside the light guide 101 (the secondpassivation sub-layer 232 and The second etching stop sub-layer 222) dueto the light reflection on the metal. Compared with the secondimplementation, the amount of light led out from the light guide 101 inthis implementation is greatly increased.

In this implementation, the first metal film layer 91 may be made in thesame layer as the gate layer, and the pattern for forming the fourthopening may be formed at the same time as the pattern for forming viasof the source and drain. The second metal film layer 92 is made in thesame layer as the source and the drain. Of course, the OLED displaysubstrate in this implementation may also be manufactured by othermanufacturing methods.

A specific manufacturing method of the OLED display substrate in thisimplementation is as follows:

-   -   forming the gate and the first metal film layer 91 on the base        substrate 1;    -   forming the gate insulation layer 21 and the etching stop layer        22;    -   performing patterning process on the etching stop layer 22 to        form the vias corresponding to the source and drain and the        fourth opening;    -   forming the second metal film layer 92 and the source and drain;    -   forming the passivation layer 23;    -   forming the planarization layer 8, and performing patterning        process to form the fifth opening;    -   forming the anode 3, the pixel definition layer 7, the cathode        5, and the light emitting layer 4 located in the pixel region        defined by the pixel definition layer 7.

In another implementation (fourth implementation) of the embodiment, alayout of components and wires of the circuit of the OLED displaysubstrate in the embodiment is shown in FIG. 10a , and a schematicdiagram of the film layer structure of the OLED display substratecorresponding to FIG. 10a is shown in FIG. 11a . The light guide 101includes a plurality of row light guides 01 arranged in parallel withdata lines, the number of the row light guides 01 is equal to the numberof rows of the pixel regions, and each row of the pixel regions isconnected to one corresponding row light guide 01, and the lightpropagates along a straight line. Compared with the layout in FIG. 3a ,the change of the light propagation angle caused by the turning of thelight is reduced, thereby reducing the phenomenon of reduction of thetotal reflected light.

In this implementation, the pixel definition layer 7 includes a firstpixel definition sub-layer 102 and a second pixel definition sub-layer103 that are stacked. The light guide 101 is located between the firstpixel definition sub-layer 102 and the second pixel definition sub-layer103, and the light guide 101 includes a contact portion exposed outsidethe pixel definition layer 7 to be in contact with the light emittinglayer 4.

In this implementation, the refractive index of the light guide 101 isgreater than the refractive index of the pixel definition layer 7.

The larger the refractive index of the light guide 101 relative to therefractive index of the pixel defining layer 7 is, the better, therebyenhancing the total reflection of light in the light guide 101, and thusenabling the light to going out along the light guide 101.

In this implementation, the light guide 101 includes a first side 1011in contact with the light emitting layer 4 and a second side 1012opposite to the first side 1011, and the contact portion is located onthe first side 1011. In order to increase the amount of light led outfrom the light guide 101, a concave-convex structure is provided on thesecond side 1012 so that the light entering the light guide is totallyreflected on the second side 1012.

The arrangement of the concave-convex structure increases thepropagation angle of light, allowing more light to be totally reflectedat the interface between the light guide 101 and the pixel defininglayer 7. Of course, there can be other ways to increase the amount ofcollected light, which is not limited here.

A specific manufacturing method of the OLED display substrate in thisimplementation is as follows:

-   -   forming the thin film transistor array layer 2 on the base        substrate 1;    -   forming the planarization layer 8;    -   forming the anode 3, and performing patterning process;    -   forming the first pixel definition sub-layer 102 and performing        patterning process on it;    -   forming the light guide 101 on the first pixel definition        sub-layer 102 and performing patterning process;    -   forming the second pixel definition sub-layer 103 and performing        patterning process;    -   wherein the second pixel definition sub-layer 103 should be        arranged such that the contact portion of the light guide 101        used to be in contact with the light emitting layer 4 is not        covered (that is, the contact portion is not covered by the        second pixel definition sub-layer 103), so that the light guide        101 can be in contact with the light emitting layer 4 directly        to receive the incoming light; the second side 1012 of the light        guide 101 (the side that is opposite to the first side 1011 on        which the contact portion is provided) is covered so as to        achieve the total reflection of light.    -   forming the light emitting layer 4 in the pixel regions defined        by the pixel definition layer 7 composed of the first pixel        definition sub-layer 102 and the second pixel definition        sub-layer 103;    -   forming the cathode layer 5 and an encapsulation layer 6        sequentially.

In another implementation (fifth implementation) of the embodiment, alayout of components and wires of the circuit of the OLED displaysubstrate in the embodiment is shown in FIG. 10b , and a schematicdiagram of the film layer structure of the OLED display substratecorresponding to FIG. 10b is shown in FIG. 11b . The light guide 101includes a plurality of row light guides 01 arranged in parallel withdata lines, the number of the row light guides 01 is equal to the numberof rows of the pixel regions, and each row of the pixel regions isconnected to one corresponding row light guide 01, and the lightpropagates along a straight line. Compared with the layout in FIG. 3a ,since the light propagates along a straight line, the change of thelight propagation angle caused by the turning of the light is reduced,thereby reducing the phenomenon of reduction of the total reflectedlight.

In this implementation, the thin film transistor array layer 2 includesa gate insulation layer 21, a first planarization layer 81, an etchingstop layer 22, a pas sivation layer 23, and a second planarization layer82 provided on the base substrate 1;

-   -   a first opening is provided at a first position of the gate        insulation layer 21, the first planarization layer 81 is located        in the first opening;    -   a second opening is provided at a second position of the etching        stop layer 22 and the passivation layer 23, the second opening        penetrates the etching stop layer 22 and the passivation layer        23, as shown in FIG. 7, a portion of the etching stop layer 22        in the second opening forms a first etching stop sub-layer 221,        the second planarization layer 82 is filled between the first        etching stop sub-layer 221 and rest of the etching stop layer        22, a portion of the passivation layer 23 in the second opening        forms a first passivation sub-layer 231, the second        planarization layer 82 is filled between the first passivation        sub-layer 231 and rest of the passivation layer 23;    -   the second planarization layer 82 has a third opening at the        second position to expose the first passivation sub-layer 231,        so that the first passivation sub-layer 231 leads light out of        the light emitting layer 4 (through the anode 3), wherein        orthographic projections of the second and third openings on the        base substrate fall within an orthographic projection of the        first opening on the base substrate.

The first etching stop sub-layer 221 and the first passivation sub-layer231 jointly form a light guide structure, which functions similarly tothe light guide 101 described above with reference to FIG. 4.

In this implementation, the refractive index of the etching stop layer22 is greater than the refractive index of the first planarization layer81, the refractive index of the etching stop layer 22 is greater thanthe refractive index of the second planarization layer 82, therefractive index of the passivation layer 23 is greater than therefractive index of the first planarization layer 81, and the refractiveindex of the passivation layer 23 is greater than the refractive indexof the second planarization layer 82.

With the above solution, the light from the light emitting layer 4enters the first passivation sub-layer 231 and the first etching stopsub-layer 221, and is totally reflected at the interface between thefirst passivation sub-layer 231 and the second planarization layer 82,and is totally reflected at the interface between the first etching stopsub-layer 221 and the first planarization layer 81, so that the lightpropagates in the light guide 101 formed by the first passivationsub-layer 231 and the first etching stop sub-layer 221, and is led out.

The manufacturing method of the OLED display substrate in thisimplementation is as follows:

-   -   forming a gate layer and a gate insulation layer on the base        substrate 1;    -   etching away the gate insulation layer at a position (the first        position) of the orthographic projection of the light guide 101        on the gate insulation layer in the planar layout shown in FIG.        11b , to form the first opening, and then forming a first        planarization layer 81 on the first opening;    -   forming an IGZO (indium gallium zinc oxide) film layer, an        etching stop layer 22, a source, a drain, and a passivation        layer 23 sequentially;    -   etching the passivation layer 23 and the etching stop layer 22        to form the second opening penetrating the passivation layer 23        and the etching stop layer 22 (the passivation layer 23 and the        etching stop layer 22 located in the second opening are named        the first passivation sub-layer 231 and the first etching stop        sub-layer 221, respectively);    -   forming a second planarization layer 82, wherein a part of the        second planarization layer 82 is filled in the second opening        and in contact with the first planarization layer 81, so as to        cover the first passivation sub-layer 231 and the first etching        stop sub-layer 221;    -   etching the second planarization layer 82 to form a third        opening that exposes the first passivation sub-layer 231;    -   the third opening is arranged to make the light emitting layer 4        be in contact with the first passivation sub-layer 231 after the        light emitting layer 4 is formed, so that light can propagate in        a total reflection manner in the light guide 101 composed of the        first passivation sub-layer 231 and the first etching stop        sub-layer 221.

It should be noted that the anode 3 is made of a transparent conductivematerial, which does not affect the light from the light emitting layer4 entering the first passivation sub-layer 231.

In another implementation (sixth implementation) of the embodiment, alayout of components and wires of the circuit of the OLED displaysubstrate in the embodiment is shown in FIG. 10b , and a schematicdiagram of the film layer structure of the OLED display substratecorresponding to FIG. 10b is shown in FIG. 11b . The light guide 101includes a plurality of row light guides 01 arranged in parallel withdata lines, the number of the row light guides 01 is equal to the numberof rows of the pixel regions, that is to say, each row of the pixelregions is connected to one corresponding row light guide 01, and thelight propagates along a straight line. Compared with the layout in FIG.3a , since the light propagates along a straight line, the change of thelight propagation angle caused by the turning of the light is reduced,thereby reducing the phenomenon of reduction of the total reflectedlight.

The thin film transistor array layer 2 includes a gate insulation layer21, a gate, a first metal film layer 91, an etching stop layer 22, apassivation layer 23, a second metal film layer 92, and a planarization8 provided on the base substrate 1;

-   -   the first metal film layer 91 and the gate are manufactured in a        same layer;    -   a fourth opening penetrating the etching stop layer 22 is        provided on the passivation layer 23 to form a second etching        stop sub-layer 222 and a second passivation sub-layer 232, the        second metal film layer 92 is located in the fourth opening and        makes contact with the first metal film layer 91 to cover the        second passivation sub-layer 232 and the second etching stop        sub-layer 222;    -   the planarization layer 8 has a fifth opening to expose the        second passivation sub-layer 232;    -   the second etching stop sub-layer 222 and the second passivation        sub-layer 232 constitutes the light guide 101.

With the above technical solution, since the cathode 5 is above thelight emitting layer 4, all the light emitted by the light emittinglayer 4 is confined to propagate inside the light guide 101 (the secondpassivation sub-layer 232 and The second etching stop sub-layer 222) dueto the light reflection on the metal. Compared with the fifthimplementation, the amount of light led out from the light guide 101 inthis implementation is greatly increased.

In this implementation, the first metal film layer 91 may be made in thesame layer as the gate layer, and the pattern for forming the fourthopening may be formed at the same time as the pattern for forming viasof the source and drain. The second metal film layer 92 is made in thesame layer as the source and the drain. Of course, the OLED displaysubstrate in this implementation may also be manufactured by othermanufacturing methods.

A specific manufacturing method of the OLED display substrate in thisimplementation is as follows:

-   -   forming the gate and the first metal film layer 91 on the base        substrate 1;    -   forming the gate insulation layer 21, the etching stop layer 22,        and the passivation layer 23;    -   performing patterning process on the etching stop layer 22 and        the passivation layer 23 to form the vias corresponding to the        source and drain and the fourth opening;    -   forming the second metal film layer 92 and the source and drain;    -   forming the planarization layer 8, and performing patterning        process to form the fifth opening;    -   forming the anode 3, the pixel definition layer 7, the cathode        5, and the light emitting layer 4 located in the pixel region        defined by the pixel definition layer 7.

The embodiment further provides an OLED display device including theabove OLED display substrate and a brightness compensation mechanismwhich is connected to the light guide 101 to collect brightnessinformation of the light emitting layer 4 and compensates brightness ofa corresponding pixel region according to the brightness information.

By replacing the sensing line in FIG. 1a by the light guide 101, thecollection of the brightness of each pixel can be realized, therebycalculating the brightness grayscale curve of each pixel, thencalculating the amount of grayscale that needs to be compensated, andthus realizing the brightness difference compensation of the display.Compared with the structure of the existing OLED device, its structureremoves the electrical parameter sensing structure and adds the opticalparameter sensing channel. Since the ultimate purpose of the electricalcompensation is to correct the difference in brightness, the opticalcompensation used in the OLED display device in the present embodimentis more direct than the electrical compensation, and has the advantagesof better compensation effect and simple structure.

In the embodiment, the brightness compensation mechanism includes:

-   -   a brightness information collection module configured to collect        the brightness information of the light emitting layer 4 in each        pixel region, the brightness information including brightness        corresponding to a plurality of grayscales in one-to-one manner;    -   a grayscale brightness curve acquisition module configured to        acquire a measured grayscale brightness curve of each pixel        region according to the brightness information;    -   a grayscale compensation value acquisition module configured to        compare the measured grayscale brightness curve with a standard        grayscale brightness curve to acquire a grayscale compensation        value of a preset grayscale;    -   a compensation module configured to perform brightness        compensation according to the grayscale compensation value.

In the embodiment, a brightness correction module is further provided,which includes:

-   -   a standard photoelectric sensor connected to the light guide 101        to acquire a measured brightness L1 of the light emitting layer        4 in a current pixel region;    -   an image sensor configured to acquire an actual brightness L2 of        the current pixel region;    -   a brightness correction coefficient acquisition unit configured        to acquire a brightness correction coefficient A=L2/L1 according        to the measured brightness L1 and the actual brightness L2;    -   the brightness information acquired by the brightness        information collection module is a product of a first brightness        acquired through the light guide 101 and the brightness        correction coefficient.

The parameters of individual sensors are different to a certain extent,and the luminous brightness of any position in each pixel region arealso different to a certain extent. The present of the brightnesscorrection module reduces the difference in the brightness informationcollection caused by the difference in sensor parameters, and improvesthe accuracy of brightness collection.

The embodiment further provides a brightness compensation method appliedto the above OLED display device, which includes steps of:

-   -   collecting the brightness information of the light emitting        layer 4 in each pixel region, specifically, selecting a pixel        region in the i-th row and the j-th column to make it emit        light, and performing brightness collection through a        photoelectric sensor connected to the light guide 101;    -   acquiring a measured grayscale brightness curve of each pixel        region according to the brightness information, specifically,        selecting K different grayscales from all grayscales for        measurement, and lighting the K grayscales separately; here,        lighting the individual pixel regions one by one; measuring the        brightness information of each pixel region, from which the        grayscale brightness curve of each pixel region can be obtained        by fitting;    -   comparing the measured grayscale brightness curve with a        standard grayscale brightness curve to acquire a grayscale        compensation value of a preset grayscale, specifically,        comparing the measured grayscale brightness curve with a        standard grayscale brightness curve to calculate the brightness        corresponding to a grayscale G in the standard grayscale        brightness curve and an actual grayscale value G′ in the        measured grayscale brightness curve, and obtaining A=G′-G as the        grayscale compensation value of a target brightness;    -   performing brightness compensation according to the grayscale        compensation value, specifically, calculating a compensated        grayscale according to the grayscale compensation value and a        displayed grayscale provided by a signal generator, and        outputting the same to a row-and-column selection control unit        to control a display screen to display.

The above are the preferred embodiments of the present disclosure. Itshould be noted that for those of ordinary skill in the art, withoutdeparting from the principles described in the present disclosure,several improvements and modifications can be made. These improvementsand modifications should also be regarded as the protection scope ofthis disclosure.

1-17. (canceled)
 18. An OLED display substrate, comprising a basesubstrate, a thin film transistor array layer and a planarization layeron the base substrate, and an anode, a pixel definition layer, acathode, and a light emitting layer on a side of the planarization layeraway from the base substrate, the pixel definition layer defining pixelregions, the light emitting layer being located on a side of the pixeldefinition layer away from the base substrate, the display substratefurther comprising a light guide that is in contact with the lightemitting layer and is used to lead out light from the light emittinglayer, so as to test the led-out light and adjust light emission. 19.The OLED display substrate according to claim 18, wherein the pixeldefinition layer comprises a first pixel definition sub-layer and asecond pixel definition sub-layer stacked in a direction away from thebase substrate, the light guide is located between the first pixeldefinition sub-layer and the second pixel definition sub-layer, and thelight guide comprises a contact portion exposed outside the pixeldefinition layer to be in contact with the light emitting layer.
 20. TheOLED display substrate according to claim 19, wherein a refractive indexof the light guide is greater than a refractive index of the pixeldefinition layer.
 21. The OLED display substrate according to claim 19,wherein the light guide comprises a first side in contact with the lightemitting layer and a second side opposite to the first side, the contactportion is located on the first side, and a concave-convex structure isprovided on the second side so that light entering the light guide istotally reflected on the second side.
 22. The OLED display substrateaccording to claim 19, wherein the light guide comprises a plurality ofrow light guides arranged in parallel with data lines, a number of therow light guides is equal to a number of rows of the pixel regions, andeach row of the pixel regions is connected to one corresponding rowlight guide.
 23. The OLED display substrate according to claim 22,wherein the light guide further comprises at least one column lightguide, and the at least one column light guide intersects the row lightguides.
 24. The OLED display substrate according to claim 18, whereinthe thin film transistor array layer comprises a gate insulation layer,a first planarization layer, an etching stop layer, a passivation layer,and a second planarization layer provided on the base substrate; a firstopening is provided at a first position of the gate insulation layer,the first planarization layer is located in the first opening; a secondopening is provided at a second position of the etching stop layer andthe passivation layer, the second opening penetrates the etching stoplayer and the passivation layer, a portion of the etching stop layer inthe second opening forms a first etching stop sub-layer, the secondplanarization layer is filled between the first etching stop sub-layerand rest of the etching stop layer, a portion of the passivation layerin the second opening forms a first passivation sub-layer, the secondplanarization layer is filled between the first passivation sub-layerand rest of the passivation layer; the second planarization layer has athird opening at the second position to expose the first passivationsub-layer, the first etching stop sub-layer and the first passivationsub-layer constitutes the light guide, wherein the light guide furthercomprises an anode which is provided between the first passivationsub-layer and the light emitting layer, wherein orthographic projectionsof the second and third openings on the base substrate fall within anorthographic projection of the first opening on the base substrate. 25.The OLED display substrate according to claim 24, wherein a refractiveindex of the etching stop layer is greater than a refractive index ofthe first planarization layer, the refractive index of the etching stoplayer is greater than a refractive index of the second planarizationlayer, a refractive index of the passivation layer is greater than therefractive index of the first planarization layer, and the refractiveindex of the passivation layer is greater than the refractive index ofthe second planarization layer.
 26. The OLED display substrate accordingto claim 18, wherein the thin film transistor array layer comprises agate insulation layer, a gate, a first metal film layer, an etching stoplayer, a passivation layer, a second metal film layer, and aplanarization layer provided on the base substrate; the first metal filmlayer and the gate are manufactured in a same layer and formed at afirst position; a fourth opening is provided at a second position of theetching stop layer and the passivation layer, the fourth openingpenetrates the etching stop layer and the passivation layer, a portionof the etching stop layer in the fourth opening forms a second etchingstop sub-layer, the second metal film layer is filled between the secondetching stop sub-layer and rest of the etching stop layer, a portion ofthe passivation layer in the fourth opening forms a second passivationsub-layer, the second metal film layer is filled between the secondpassivation sub-layer and rest of the passivation layer; theplanarization layer has a fifth opening at the second position to exposethe second passivation sub-layer; the second etching stop sub-layer andthe second passivation sub-layer constitutes the light guide, wherein anorthographic projection of the fifth opening on the base substrate fallswithin an orthographic projection of the fourth opening on the basesubstrate.
 27. A manufacturing method of OLED display substrate,comprising: forming a thin film transistor array layer on a basesubstrate; forming a planarization layer; forming an anode and a pixeldefinition layer on a side of the planarization away from the basesubstrate; forming a light emitting layer on a side of the pixeldefinition layer away from the base substrate; forming a light guide,the light guide being in contact with the light emitting layer and usedto lead out light from the light emitting layer to test the led-outlight and adjust light emission; and forming a cathode on the lightemitting layer.
 28. The manufacturing method according to claim 27,wherein the pixel definition layer comprises a first pixel definitionsub-layer and a second pixel definition sub-layer, and after the step offorming the planarization layer, the method comprises: forming the anodeand performing patterning process; forming the first pixel definitionsub-layer and performing patterning process; forming the light guide onthe first pixel definition sub-layer and performing patterning process;forming the second pixel definition sub-layer on the first pixeldefinition sub-layer and the light guide, and performing patterningprocess; forming the light emitting layer on the second pixel definitionsub-layer; and forming the cathode on the light emitting layer.
 29. Themanufacturing method according to claim 27, wherein the light guide iscomposed of a passivation layer and an etching stop layer, and themethod comprises: forming a gate layer and a gate insulation layer onthe base substrate; etching the gate insulation layer at a firstposition to form a first opening; forming a first planarization layer inthe first opening; forming the etching stop layer and the passivationlayer; etching the passivation layer and the etching stop layer to forma second opening penetrating the passivation layer and the etching stoplayer, a portion of the etching stop layer in the second opening forminga first etching stop sub-layer, a portion of the passivation layer inthe second opening forming a first passivation sub-layer; forming asecond planarization layer, wherein a part of the second planarizationlayer filled in the second opening and the first passivation layer arein contact with each other, so as to cover the first passivationsub-layer and the first etching stop sub-layer; etching the secondplanarization layer at a second position to form a third openingexposing the first passivation sub-layer.
 30. The manufacturing methodaccording to claim 27, wherein the light guide is composed of apassivation layer and an etching stop layer, and the method comprises:forming a gate and a first metal film layer in a same layer on the basesubstrate, wherein the first metal film layer is formed at a firstposition; forming a gate insulation layer, a passivation layer and anetching stop layer; performing patterning process on the passivationlayer and the etching stop layer to form a fourth opening, a portion ofthe etching stop layer in the fourth opening forming a second etchingstop sub-layer, a portion of the passivation layer in the fourth openingforming a second passivation sub-layer; forming a second metal filmlayer in the fourth opening, the second metal film layer being filledbetween the second etching stop sub-layer and rest of the etching stoplayer and filled between the second passivation sub-layer and rest ofthe passivation layer; forming the planarization and performingpatterning process to form a fifth opening; forming the node, the pixeldefinition layer, the cathode, and the light emitting layer in pixelregions defined by the pixel definition layer.
 31. An OLED displaydevice, comprising the OLED display substrate according to claim 18, anda brightness compensation mechanism which is connected to the lightguide to collect brightness information of the light emitting layer andcompensates brightness of a corresponding pixel region according to thebrightness information.
 32. The OLED display device according to claim31, wherein the brightness compensation mechanism comprises: abrightness information collection module configured to collect thebrightness information of the light emitting layer in each pixel region,the brightness information comprising brightness corresponding to aplurality of grayscales in one-to-one manner; a grayscale brightnesscurve acquisition module configured to acquire a measured grayscalebrightness curve according to the brightness information; a grayscalecompensation value acquisition module configured to compare the measuredgrayscale brightness curve with a standard grayscale brightness curve toacquire a grayscale compensation value of a preset grayscale; acompensation module configured to perform brightness compensationaccording to the grayscale compensation value.
 33. The OLED displaydevice according to claim 32, further comprising a brightness correctionmodule which comprises: a standard photoelectric sensor connected to thelight guide to acquire a measured brightness L1 of the light emittinglayer in a current pixel region; an image sensor configured to acquirean actual brightness L2 of the current pixel region; a brightnesscorrection coefficient acquisition unit configured to acquire abrightness correction coefficient A=L2/L1 according to the measuredbrightness L1 and the actual brightness L2; the brightness informationacquired by the brightness information collection module is a product ofa first brightness acquired through the light guide and the brightnesscorrection coefficient.
 34. A brightness compensation method applied tothe OLED display device according to claim 31, comprising steps of:collecting the brightness information of the light emitting layer ineach pixel region; acquiring a measured grayscale brightness curveaccording to the brightness information; comparing the measuredgrayscale brightness curve with a standard grayscale brightness curve toacquire a grayscale compensation value of a preset grayscale; performingbrightness compensation according to the grayscale compensation value.35. The OLED display device according to claim 31, wherein the pixeldefinition layer comprises a first pixel definition sub-layer and asecond pixel definition sub-layer stacked in a direction away from thebase substrate, the light guide is located between the first pixeldefinition sub-layer and the second pixel definition sub-layer, and thelight guide comprises a contact portion exposed outside the pixeldefinition layer to be in contact with the light emitting layer.
 36. TheOLED display device according to claim 35, wherein a refractive index ofthe light guide is greater than a refractive index of the pixeldefinition layer.
 37. The OLED display device according to claim 35,wherein the light guide comprises a first side in contact with the lightemitting layer and a second side opposite to the first side, the contactportion is located on the first side, and a concave-convex structure isprovided on the second side so that light entering the light guide istotally reflected on the second side.